1. The Field of the Invention
The present invention generally relates to the field of light curing devices. More particularly, the invention relates to light curing devices including one or more light emitting diodes (e.g., LEDs) for providing light curing wavelengths configured to cure polymerizable compositions.
2. The Relevant Technology
In the field of dentistry, dental cavities or preparations are often filled and/or sealed with photosensitive polymerizable compositions that are cured by exposure to radiant energy, such as visible light. These compositions, commonly referred to as light-curable compositions, are placed within dental cavity preparations or onto dental surfaces where they are subsequently irradiated by light. The radiated light causes photosensitive components within the compositions to initiate polymerization of polymerizable components, thereby hardening the light-curable composition within the dental cavity preparation or other dental surface.
Light-curing devices are typically configured with an activating light source, such as a quartz-tungsten-halogen (QTH) bulb or light emitting diodes (LEDs). QTH bulbs generate a broad spectrum of light that can be used to cure a broad range of polymerizable compositions. QTH bulbs generate substantial waste heat and require bulky surrounding structure to draw waste heat away from the bulb and to dissipate the waste heat.
Use of LED light sources has been a significant improvement in dental curing devices. LEDs are smaller than QTH bulbs and generally radiate light at a narrow range surrounding a specific peak wavelength. They often require significantly less input power to generate a desired output of radiation. In addition, LED light sources provide a longer life (e.g., tens of thousands of hours or more) than QTH bulbs. However, thermal management (e.g., dissipating heat) is still an issue with devices which include LED light sources.
While prior LED curing light devices may produce less waste heat than bulb curing devices, LED curing devices still tend to produce waste heat that significantly raises the temperature of the LED and immediately surrounding structures during illumination. This increase in temperature may reduce the useful life of the LED. LEDs can burn out due to overheating within a matter of minutes, requiring replacement of the LED light source if the heat is not dissipated.